Methods, computer program products, and systems are presented. The method computer program products, and systems can include, for instance: examining, by machine logic, interactions data specifying attributes of interactions with posted social media promotional content promoting a product, wherein the product is subject to an initiated purchase transaction, and wherein the interactions include interactions by a plurality of users; attributing, by machine logic, referral credit for the purchase transaction to users of the plurality of users based on the examining; and providing one or more output based on the attributing.